Air inlet cover

Abstract

In a first aspect, the present invention provides an air inlet cover (1) comprising a grille (2) having a plurality of radial elements (3) radiating from a center of said grille (2), each said radial element (3) comprising a vane (4) having a leading edge (5) for positioning further from a fan and a trailing edge (6) for positioning closer to a fan, the leading edge (5) of each said vane being offset from the respective trailing edge (6) thereof by substantially the same angular amount (α) for each said vane (4), whereby the vanes are pitched more steeply closer to the center of said grille (2) than remote from the center of said grille, and a circumferential element (7) comprising a bell-shaped mouth enclosing said vanes (4) and having a plurality of apertures (8) formed in a surface thereof, each respective one of said apertures (8) having a first edge (9) parallel to the pitch of a first respective vane closer to the center of said grille and a second edge (10) parallel to the pitch of a second, adjacent respective vane remote from the center of said grille. In a second aspect, the present invention also provides a power tool comprising a fan and such an air inlet cover (1). The power tool may be a garden leaf blower or a dust extraction machine, including a domestic vacuum cleaner.

1. An air inlet cover comprising a grille having: a plurality of radial elements radiating from a center of said grille, each said radial element comprising a vane having a leading edge for positioning further from a fan and a trailing edge for positioning closer to a fan, the leading edge of each said vane being offset from the respective trailing edge thereof by substantially the same angular amount for each said vane, whereby the vanes are pitched more steeply closer to the center of said grille than remote from the center of said grille, and
 a circumferential element comprising a bell-shaped mouth enclosing said vanes and having a plurality of apertures formed in a surface thereof, each respective one of said apertures having a first edge parallel to the pitch of a first respective vane closer to the center of said grille and a second edge parallel to the pitch of a second, adjacent respective vane remote from the center of said grille. 
 
     
     
       2. The air inlet cover according to  claim 1 , wherein the leading edge of each said vane has a width substantially equal to the width of the trailing edge thereof, such that the width of said vanes is substantially uniform across their depth. 
     
     
       3. The air inlet cover according to  claim 1 , further comprising a concentric element that intersect an intermediate portion of the radial element. 
     
     
       4. The air inlet cover according to  claim 3 , wherein the concentric element has a depth equal to or less than a depth of the circumferential element and contacts the trailing edge of the radial elements at a right angle. 
     
     
       5. The air inlet cover according to  claim 1 , wherein the plurality of apertures formed in the circumferential element each comprise a bar formed across each said respective aperture. 
     
     
       6. A power tool comprising:
 a fan; 
 an air inlet cover having a grill located over said fan; and 
 the grill having a plurality of radial elements radiating from a center of said grille, each said radial element comprising a vane having a leading edge for positioning further from a fan and a trailing edge for positioning closer to a fan, whereby the vanes are pitched more steeply closer to the center of said grille than remote from the center of said grille, wherein the pitch is the angle of the vane between its leading edge and trailing edge. 
 
     
     
       7. The power tool according to  claim 6  further comprising a circumferential element comprising a bell-shaped mouth enclosing said vanes and having a plurality of apertures formed in a surface thereof, each respective one of said apertures having a first edge parallel to the pitch of a first respective vane closer to the center of said grille and a second edge parallel to the pitch of a second, adjacent respective vane remote from the center of said grille. 
     
     
       8. The power tool according to  claim 7 , further comprising a concentric element that intersect an intermediate portion of the radial element. 
     
     
       9. The air inlet cover according to  claim 8 , wherein the concentric element has a depth equal to or less than a depth of the circumferential element and contacts the trailing edge of the radial elements at a right angle. 
     
     
       10. The power tool according to  claim 6 , wherein the tool is a garden leaf blower or a dust extraction machine, including a domestic vacuum cleaner. 
     
     
       11. The power tool according to  claim 6 , wherein the leading edge of each said vane has a width substantially equal to the width of the trailing edge thereof, such that the width of said vanes is substantially uniform across their depth.